Door control apparatus



Aug. 18, 1959' w. F. EAMES 0 DOOR CONTROL APPARATUS Filed July 21, 1953Fig.l.

Fi 3A 'INVENTOR L+| L-l William F. Eomes.

ATTORNEY United States Patent DOOR CONTROL APPARATUS William F. Eames,Westfield, N.J., assignor to Westinghouse Electric Corporation, E'astPittsburgh, Pa., a corporation of Pennsylvania Application July 21,1953, Serial No. 369,469

Claims. (Cl. 250-208) This invention relates to apparatus for detectingthe presence of an object in space and it has particular relation toapparatus responsive to the presence of objects in the closing path of adoor for controlling the operation of the door.

Although aspects of the invention may be employed for variousapplications wherein the presence of an object in space is to bedetected, the invention is particularly desirable for the control ofdoors. The invention may be applied to manually-operated doors but it isespecially suitable for power-operated doors such as those encounteredin elevator systems.

In an elevator system the doors of an elevator car may be under thesupervision of a car attendant or they may operate automatically, no carattendant being provided. Devices for preventing a door from striking anobject in the closing path of the door can be employed for elevatorsystems wherein an elevator car is provided with a car attendant, butthey are even more desirable for an elevator system wherein no carattendant is provided \for an elevator car.

In accordance with the invention, radiant energy is projected into spacefor the purpose of detecting the presence of an object. Preferably theradiant energy is capable of being concentrated or focussed into a beamand preferably the radiant energy is not in the portion of the spectrumvisible to the eye. Infrared radiant energy is particularly suitable.

The invention further contemplates the provision of a detector which isresponsive to the presence or absence of the radiant energy. Preferablythe detector is responsive only to energy which is outside the visibleportion of the spectrum. As previously pointed out, infrared radiantenergy is particularly desirable and the detector may be responsive onlyto radiant energy in the infrared region of the spectrum.

Although a single beam of radiant energy may be employed, preferably aplurality of beams are established across an opening which is to bescanned. A separate detector is provided for each of the beams. In aprefer-red embodiment of the invention, interruption of a first numberof the beams may be employed for retarding closure of a door which isintended to close the opening scanned by the beams. Interruption of agreater number of the beams is then utilized for further retarding orstopping or reversing the door.

The beams may be of fixed dimension for all conditions of dooroperation. Preferably the beams are arranged to shorten as the doorsclose. To this end, each transmitter device utilized for projecting abeam into the opening or each detector device utilized for detecting thepresence or absence of the beam or both may be mounted for movement inaccordance with movement of the door relative to the opening. In apreferred embodiment of the invention the devices are mounted on edgesof the doors which are the leading edges during closing operations.

The door edge on which one or more of the devices may be mountedpreferably is separable as a unit from the remainder of the door. Forcenter-opening doors, a row of transmitter devices for projectingradiant energy may be mounted on the leading edge of one of the doorswhereas a row of detector devices may be mounted on the leading edge ofthe remaining door.

It is therefore an object of the invention to provide improvedobject-detecting means employing non-visible radiant energy.

It is a further object of the invention to provide improvedobject-detecting means including a transmitter for producing a beam ofinfrared radiant energy and an infrared radiant-energy detector devicelocated in the path of the beam.

It is a still further object of the invention to provide improvedobject-detecting apparatus including a transmitter unit for producing aplurality of spaced radiant-energy beams across an opening and aseparate detector device responsive to such radiant energy in the pathof each ofthe beams together with translating means having varyingresponses dependent on the number of beams which are interrupted.

It is an additional object of the invention to provide a door controlmechanism including a transmitting device for directing a beam ofradiant energy alongthe closure path of the door and a radiant-energydetector device in the path of the beam wherein the devices are mountedto approach each other as the door closes.

It is also an object of the invention to provide a door controlmechanism wherein a pltu'ality of beams of infrared energy areestablished across the closing path of the door and wherein a separatedetector device is-provided for detecting the presence or absencesubstantially of each of the beams together with mechanism responsive tothe condition of the detector devices for retarding the closure of thedoor as a function of the number of beams which are interrupted.

It is another object of the invention to provide adoor having aseparable edge and havinga plurality of devices for projecting ordetecting radiant energy positioned along the separable edge.

It is still another object of the invention to provide center-openingdoors having operating means for closing and opening the doors togetherwith safety mechanism including a plurality of pairs of devices, eachpair including a radiant-energy transmitter and a. radiant-energydetector positioned to receive radiant energyprojected by thetransmitter device, one of the devices in each ofthe pairs being locatedon one of the center opening doors and the remaining devices beinglocated on the remaining one of the center-opening doors.

It is still another object of the invention to provide a system as setforth in the preceding paragraph together with mechanism controlled bythe detector devices and responsive to interruption of the beams forretanding closure of the doors to an extent dependent on the number ofbeams interrupted.

Other objects of the invention will be apparent from the followingdescription taken in conjunction with the accompanying drawing, inwhich:

Figure 1 is a view in elevation with parts broken away of an elevatorcar embodying the invention;

Fig. 2 is a view in section with parts broken away taken along the line11-11 of Fig. 1;

Fig. 3 is a schematic view in straight-line form illustrating controlcircuits associated with the elevator car of Fig. l; and

Fig. 3A is a view of electromagnetic switches and relays employed in thecircuits of Fig. 3. Corresponding contacts and coils in Figs. 3 and 3Aare substantially in horizontal alignment.

The invention may be applied to any desired arrangement of doors. Forexample, the invention may be utilized for controlling the operation ofside-opening, centeropening, single-speed or two-speed doors of typescommonly encountered in elevator systems. In order to simplify itspresentation, the invention is assumed to be applied to .an elevator caremploying center-opening doors as illustrated in the McCormick Patent2,235,3 80. Insofar as is practicable, corresponding components of theMcCormick apparatus and the apparatus shown in the attached drawing areillustrated similarly and bear similar reference characters. Thesecorresponding components are as follows:

Apparatus list L+1, L1Direct current source of electric energy OR-Dooropening relay CR--Door closing relay CSCar switch C-Car door motorhaving armature CA and field winding CF 1K-First opening resistor relayZK-Second opening resistor relay 3KFirst closing resistor relayLController LO-Lirnit switch on opening (operated by controller) LCLimitswitch on closing (operated by controller) OL1-First opening cam on doorand gate (operated by controller) OLZ-Second opening cam on door andgate (operated by controller) CL3First closing cam (operated bycontroller) CL4-Second closing cam on gate only (operated by controller)30Car }Horizontally sliding center opening doors 37--Overhead track43-Driving pulley or wheel 44Driving belt 45-Driven pulley or sheave46Shaft 48- }Sprocket wheel Hangers 49- Sprocket chains 51- BracketsResistors Condensers The components in the above list may be identicalin the aforesaid McCormick patent and in the present drawing with theexception of the doors 35 and 36 and the door opening relay OR. In thepresent case, each of the doors is divided into two units or parts. Forexample, the door 35 is provided with a main part or unit 35A and anedge unit 35B which is separably attached to the unit 35A in anysuitable manner as by means of screws 100. This edge unit 35B is locatedat the leading edge of the door during the closing movement of the doorand may be referred to as a leading edge unit.

In an analogous manner the door 36 in the present case includes a doorunit 36A and a leading edge unit 36B which is separably attached to themain door unit 36A. A set of break contacts R7 is added to the dooropening relay OR of the McCormick patent. With these exceptions, thecomponents in the above list may be identical for the McCormick patentand for the present drawing. For this reason the following discussionwill be directed primarily to the additional subject matter hereinpresented. For a detailed discussion of the components in the abovelist, reference may be made to the McCormick patent.

During a closing operation of the doors 35 and 36, it is highlydesirable that the doors be prevented from striking an object located inthe closing paths thereof. To this end a transmitting device IT isprovided for projecting across the door opening radiant energy. Adetector device 1D is located in the path of such radiant energy. Byinspection of Fig. 1 it will be observed that the transmitting device ITand the detector device ID are located on opposite sides of the opening.These devices are shown on a larger scale in Fig. 2.

The radiant energy projected by the transmitter device 1T may have afrequency selected from a wide range. For example, the radiant energymay have a frequency in the ultrahigh radio frequency range if theobjects entering the opening are opaque to such frequencies. Suchobjects may be constructed of an electroconductive material.

Preferably the radiant energy projected by the transmitter device 1Tshould be capable of being compacted or focussed into a compact beam.This not only improves the efliciency of the apparatus, but it preventsstray refiections of the radiant energy from objects which are outsidethe closing path of the doors.

If the objects entering the opening are of an inanimate nature, theradiant energy conceivably may be produced by a radioactive pelletconstituting the transmitter 1T. However, if the objects comprise livingcells or tissue, the radiant energy should be incapable of injuring suchcells or ltissue.

The transmitter device 1T may be designed to project visible light intothe opening. However, since numerous sources of light are present, bothwithin the elevator car and in the corridors served by the elevator car,the possibility of false operation of the apparatus due to the externalsources is present and if an attempt is made to shield the detectordevice ID from other light sources, it becomes difficult to clean andmaintain the detector device. For these and other reasons, non-visibleradiant energy is desirable.

Preferably the transmitter device ET is designed to transmit a beam ofinfrared radiant energy. To this end, the transmitter device may includea heater or filament 102 which is located within a tube 104. A filament102 may be constructed of a suitable resistance material such asnichrome which when heated by an electric current emits infrared radiantenergy.

The end of the tube 104 through which the beam of radiant energy istransmitted preferably is closed by a lens which focusses the radiantenergy into a compact beam which extends across the opening between thedoors. It will be understood that the heater 102 need not be enclosed ina vacuum and may be of sturdy construction. If the heater generatesradiation outside the desired range, a filter may be employed or thelens 106 may be constructed of a filter material for permitting thepassage of only the desired radiant energy, in this case, infraredradiant energy.

The energy required for the heater 102 is quite small, and the infraredbeam resulting may have such a low energy level that it is notperceptible by persons intercepting the beam. If desired, the energylevel may be increased for the purpose of subjecting a personinterrupting the beam to substantial heat. The resulting sensation ofheat discourages a person from intentionally holding open the doors.However, in most applications, it will be assumed that the energy levelis below the Value producing heat substantially perceptible by a person.

By inspection of Fig. 2 it will be noted that the transmitter device ETis located in the leading edge unit 355. The leading edge unit 353 maybe constructed of a channel 108 having an open end which is proportionedto receive the edge of the door unit 35A, to which it is detachablysecured by the screws 100. As shown in Fig. 2, the transmitter device isrecessed in an opening provided in the web of the channel. Electriccurrent for the heater 102 is supplied through a cable 110 which extendsthrough the channel 108'. By reference to Fig. 1 it will be noted thatthe cable 110 is of a flexible nature to permit movement of the doorunit and may be attached to a lever 112 which is pivotally secured tothe elevator car. The lever is biased by a spring 114 to maintain thecable 110 taut.

The ends of the channel 108 may be left open to provide air circulationwhich carries heat from the transmitter device 1T. Additionalventilation may be provided in any suitable manner if so desired.

The detector device 1D is mounted in a channel 116 which is detachablysecured to the edge of the door unit 36A. The construction is similar tothat discussed for the mounting of the transmitter device IT.

The detector device 1D may be of any type responsive to the radiantenergy received from the transmitter device 1T. Thus for infraredradiant energy the detector device 1D may be of the photoemissive type,the photoconductive type or the photovoltaic type as desired. Theterminals of the detector device are connected through a suitable cable118 and through a suitable source of voltage, if employed, to twoterminals 120 and 122. The cable 118 is similar to the cable 110 and maybe similarly secured to the elevator car.

In a preferred embodiment of the invention, the detector device 1Dcomprises a small wafer 124 of germanium which is mounted in anelectroconductive ring 126. The wafer has a dimple on one face in whicha collector electrode 128 is located. The ring 126 and the collectorelectrode 128 constitute the terminals of the detector device. Theseterminals are connected in series with a suitable source of directVoltage represented by polarity markings and across the terminals 120and 122.

The radiant energy received from the transmitter device IT is applied tothe face of the wafer 124 opposite the collector electrode 128. In thisarea, the wafer may have a thickness of the order of .003 of an inch.Preferably the radiant energy is focussed on the wafer by means of asuitable lens 130. If desired, a filter may be employed or the lens 130may be constructed of a filter capable of transmitting only infraredradiant energy. This prevents excitation of the wafer 124 by visiblelight.

Any suitable translating device may be connected to the terminals 120and 122. In the present case, a relay 1P has its coil connected directlyacross the terminals. If desired, an amplifier (not shown) may beinserted between the terminals 120 and 122 on the one hand and the relayIP for the purpose of amplifying the energy received from the terminals.However, the germanium wafer detector device may be designed to providesuificient output to operate the relay 1P directly.

As long as :the detector device 1D is receiving infrared radiant energy,the relay 1P is energized and picked up and the break contacts 1P1 areopened. If the beam is interrupted in any way as by the presence of aperson in the path of the beam, the relay 1? is dropped out and thebreak contacts 1P1 are closed. As hereinafter pointed out, the closingof the contacts 1P1 may be employed for retarding closure of the cardoors.

If desired the transmitter device IT and the detector device 1D may bemounted on portions of the elevator car adjacent the opening, butseparate from the doors 35 and 36. However, it is desirable to mount thedevices in such a manner that as the elevator car doors close, thedistance between the devices decreases. Such decrease is assured by themounting of one or both of the devices in the edges of the doors asherein set forth. The shortening of the distance between the devicesmakes it more unlikely that the detector device will be affected byreflected infrared radiant energy. Furthermore when the elevator doorsare completely closed, the lenses of the transmitter and detectordevices are completely protected from possible abrasion and from thedeposition of dust thereon. Furthermore by locating the device in amanner herein set forth, the lenses are completely available forcleaning.

Although a single beam may be helpful in protecting the opening betweenthe doors 35 and 36, it is advantageous to provide a plurality of beams.To this end, a plurality of transmitter devices 1T, 2T, 3T, 4T, ST and6T may be located in a row along the leading edge of the door 35. Thesetransmitter devices project a plurality of parallel beams across theopening. The trans mitter devices may be spaced apart by any desireddistance. It is contemplated that the distance between adjacenttransmitter devices need not be less than 6 inches. Such a 6-inchminimum spacing is adequate for most elevator car installations.

All of the transmitter devices are mounted in the leading edge unit 35Bin the same manner and are similarly energized through the cable 110. Ifit is necessary to service or replace the transmitter devices, thecomplete edge unit 35B containing all of the transmitter devices may beremoved from the associated door unit 35A.

A separate detector device is provided for each of the transmitterunits. Thus in Fig. l transmitter devices 1D, 2D, 3D, 4D, 5D and 6D areillustrated. These are all mounted on the leading edge of the door 36 inthe same manner and their outputs are transmitted through the cable 118to individual relays, each similar to the relay IF, and identified bythe letter P preceded by the numeral corresponding to the numeral prefixof the associated detector device. Since all of the detector devices aremounted on the leading edge unit 36B, they may be removed as a singleassembly from the door unit 36A for servicing or replacement as desired.

Fig. 3 represents the control circuits shown in Fig. 5 of the aforesaidMcCormick patent modified as shown in heavy lines. Since the inventionmay be described adequately as applied to the car doors, Fig. 3 does notdisclose the circuits for controlling the hatchway doors. However, it isto be understood that if the hatchway doors of the McCormick patent areemployed, they may be protected in the same manner discussed for the cardoors.

Translating mechanism is provided which preferably has a responsedependent on the number of beams which are interrupted. For example, thedoors may be retarded to a degree dependent on the number of beams whichare interrupted.

By inspection of Fig. 3 it will be noted that two relays A and B areadded to the control circuits of the McCormick patent. These relays willbe referred to respectively as the first retarding relay and the secondretarding relay. The relays A and B are connected between the buses L+1and L-1 for energization through a parallel circuit having 6 arms inparallel. Each of the arms includes a resistor and a separate one of therelays associated with the detector devices 1D to 6D. For example onearm includes a resistor IR and the break contacts 1P1 for the relay IF.A second arm includes a resistor 2R and break contacts 2P1. It will beunderstood that the break contacts 2P1 are open when the detector device2D receives an infrared radiant energy beam and are closed when the beamis interrupted. Thus each of the arms in the parallel circuit iscontrolled by a separate one of the detector devices 1D to 6D.

The relay A is designed to pick up when it is energized through apredetermined number of the associated parallel arms. For presentpurposes it will be assumed that the relay A picks up when it isenergized through any one of the associated parallel arms.

The relay B is designed to pick up when it is energized through a numberof arms of the associated parallel circuit larger than the numberrequired to pick up the relay A. In the present case, it will be assumedthat the relay B picks up when it is energized through any two arms ofthe associated parallel circuit. If desired the relays A and B may be ofsimilar construction but the difierence in pickup may be provided by aresistor BR which is connected in shunt with the coil of the relay B. Byadjusting the value of the resistor BR, the num ber of parallel arms ofthe associated parallel circuit through which the relay B must beenergized for the relay to pick up may be adjusted.

The first retarding relay is designed to introduce a first retardingeffect in the door closure of the elevator car. To this end, pickup ofthe relay A is accompanied by closure of the make contacts A1 to connectthrough break contacts CR7 a resistor RA across the armature CA of thecar door motor C. Such connection of the resistor decreases the currentflowing through the armature and increases the current flowing throughthe field winding CF to decrease the rate at which the doors close.Consequently if a person attempts to prevent closure of the doors byinterrupting one of the beams with his hand the doors will stillcontinue to close but at a slower rate of movement. Break contacts R7are added to the door opening relay OR of the aforesaid McCormickpatent.

Furthermore, if one of the transmitter devices or one of the detectordevices become inoperative, the doors of the elevator car can stilloperate but at a slower rate of movement until the defective device isrepaired or replaced.

Pickup of the second retarding relay B is intended to produce a furtherretarding effect on the closure of the doors. Such a retarding effectmay cause the doors to close at a still slower rate, it may stop thedoors completely or it may reopen the doors.

As shown in the preferred embodiment, the relay B in picking up opensits break contacts B1 and B3 to interrupt the closing circuit for thefield winding CF and the armature CA. At the same time the make contactsB2 close to establish an opening circuit for the door opening relay OR.Consequently, the pickup of the relay B is accompanied by reopening ofthe car doors.

The operation of the system now may be set forth. For the firstoperation it will be assumed that the retarding relays A and B bothremain deenergized. Under these circumstances the car doors operate inthe same manner discussed in the McCormick patent and may be set forthas follows:

It will be assumed that the car is in operation and is slowing down to astop at the third floor. The controller switches CL4, CL3 and LO areclosed by reason of the position of the controller L.

As the car comes into the third floor, it is assumed that the attendantthrows the car switch CS to open the car doors 35 and 36. The closing ofthe contact members CS1 energizes the door opening relay OR by thecircuit L+1, OR, LO, CS1, L1.

The closing of the contact members CR3 and 0R4 energizes the fieldwinding CF and the armature CA of the car door motor to move the cardoors to their open position, through the circuit L+1, 0R3, CF, 0R4, 13,CA, L1. The energized motor moves the chains 49 and 53 to open the cardoors and the action of the chains rotates the controller L to restoreits limit switch contact members LC to their closed position. By thetime the doors are approximately one inch open, the chains rotate thecontroller to restore its contact members CL4 to their open position.When the doors are, say, four inches open, the controller restores itscontact members CL3 to their open position. As the car doors continuetheir travel toward their open position and are, say, four inches fromtheir full open position, the controller L closes its first deceleratingcontact members 0L1, thereby energizing the first opening resistor relay1K which, in turn, closes its contact members. The closing of thecontact members 1K2 inserts a predetermined portion of the resistor 14in parallel with the armature CA of the car door motor to deceleratethat motor to slow down the car door as it nears its full open position.As the doors arrive at, say, one inch from their full open position, thecontroller L is operated to close its second decelerating switch 0L2,thereby energizing the second opening resistor relay 2K to close itscontact members by the circuit L+1, 2K, 0L2, 0R5, L-1. The closing ofthe contact members 2K2 inserts a predetermined portion of the resistor14 in parallel with the armature CA of the car door motor to deceleratethat motor to slow down the car doors so that they move softly intotheir full open position.

In the diagram of Fig. 3, the resistor r4 is shown as connected atvarious points by adjustable arrows controlled by opening and closingswitches. It should be understood that in actual practice the circuitscontrolled by the opening and closing switches may be connected to theresistor at any point or points selected by the elevator engineer andthat it is common practice to make these connections when the elevatoris installed and to change or modify them in any manner desired tosecure smooth operation of the car door motor in opening and closing thedoors with which they are associated.

As the car doors reach their open position, the controller L is operatedto open its limit switch L0 to deenergize the opening relay OR. However,inasmuch as this relay is associated with its condenser 70, it staysenergized for a very short time to give the door motors time to completetheir opening movement after the limit switch opens and also causes thedoors to be held in their full open position momentarily against theirbumpers to absorb their rebound. The opening of the contact members 0R3and 0R4 deenergizes the field winding CF and the armature CA of the cardoor motor, thereby stopping that motor. The opening of the contactmembers 0R5 deenergizes the first opening and the second openingresistor relays 1K and 2K to open their contact members fordisconnecting the resistor r2 from the circuits for the armature CA.

It will be assumed now that the passengers have entered or left the carand that the car attendant moves the car switch CS in a clockwisedirection to efiect the closing of the car doors. The movement of theswitch closes its contact members CS2, thereby energizing the doorclosing relay CR through the circuit L+ 1, CR, LC, CS2, L-l.

The closing of the contact members CR3 and CR4 energizes the car doormotor C through the circuit L-|-1, CR4, B3, CF, B1, CR3, r3, CA, L-1.The energized car door motor moves the car doors toward their closedposition and in doing so causes the chains 49 and 53 to rotate thecontroller L so that it restores the limit switch L0 to its closedposition. As the car door moves, say, one inch away from its openposition, the controller restores its switch 0L2 to its open position,and as the car door moves, say, four inches away from its open position,the controller restores the switch 0L1 to its open position, to preparethem for closing at the proper time in the opening sequence of thedoors.

As the doors arrive at, say, four inches from their closed position, thecontroller L closes its switch CL3, thereby completing the circuit forenergizing the first closing resistor relay 3K to close its contactmember 3K2. The closing of the contact members 3K2 inserts apredetermined portion of 'the resistor r4 in parallel with the armatureCA of the car door motor to cause that motor to decelerate and thus slowdown the movement of the car door as it nears its fully closed position.

As the car door gets within, say, one inch of its closed position, thecontroller L closes its switch CL4, thereby inserting a predeterminedportion of the resistor r4 in parallel circuit with the armature CA topositively check the car door motor as the car door reaches the desiredpredetermined distance from its full closed position.

When the doors are about one-half inch from their fully closed position,the controller opens its limit switch LC, thereby opening the circuitfor the door closing relay CR but the condenser 71 on this relaymaintains it in its energized conditionfor a time sufiicient for themotors to move the doors to their fully closed position and also causesthe motors to hold the doors momentarily against their bumpers to absorbthe rebound therefrom. When the relay CR becomes deenergized, it opensits contact members. The opening of the contact members CR3 andCR4deenergizes the car door motor. The opening of the contact membersCR5 removes a predetermined portion of the resistor r4 from the circuitof the armature CA of the car door motor. The opening of the contactmember CR6 deenergizes the first closing, resistor relay 3K whichrestores its contact member 3K2 to its open position.

Next it will be assumed that one of the devices such as the transmitterdevice IT has an open circuit and fails to produce a-beam of radiantenergy. Under such circumstances, the source of radiant energy isremoved from the detector device 1D and the relay 1P drops out to closeits break contacts 1P1.

As shown in Fig. 3 closure of the break contacts 1P1 completes thefollowing energizing circuit for the retarding relays: L-|-1, 1P1, IR,A, B, and BR in parallel, L.1. Such energization is insufiicient to pickup the second retarding relay B but it is suflicient to pick up thefirst retarding relay A. The relay A closes its make contacts A1 toconnect through the contacts 0R7 the resistor RA across the armature CA.This reduces the closing speed of thedoors but permits closure of thedoors at the reduced speed until the defective transmitter device isreplaced or repaired.

Let it be assumed next that a passenger attempts to prevent closure ofthe doors by advancing his foot to interrupt the radiant energytransmitted by the transmitter device 1T. The efiect of suchinterruption is to prevent radiant energy from reaching the transmitterdevice 1D and the relay 1P drops out-to close its break contacts 1P1.Consequently during the closing operation of the doors, the firstretarding relay A is picked up through the following circuit: L+1, 1P1,IR, A, B and BR in parallel, L 1. Such energization is insufiicient tocause pickup of the relay B.

The closure of the make contacts A1 connects the resistor RA through thebreak contacts 0R7 across the armature CA to reduce the speed of closureof the doors. Consequently the doors continue to close-at a reduced rateand tend'to force the foot of the person away from the door. Because ofthe slow rate-of movement of the door the personcan remove his footcompletely before the doors close.

Finally let it be assumed'that during a closing operation of the doors aperson enters theopening and interrupts at 1 least the beams transmittedfrom the transmitter devices 1T and 2T. As a result of such operation,the relays associated with the detector devices 1D and 21) both drop outand close their break contacts 1P1 and 2P1, to establish the followingcircuit: L+1, 1P1 and IR in parallel with 2P1 and 2R, A, B and BR inparallel, L1.

The second retarding relay B is now energized sufficiently to pick up.This relay opens its break contacts B1 and B3 to interrupt the closingcircuit for the field Winding CF andthe armature CA. Consequently, theelevator car doors come to-a stop.

At the same time, the secondretarding relay B closes itsmake contactsB2- to establishthe following opening circuit for the door openingrelay: L-l-l, OR, L0, B2, L-l. Since the door opening relay OR now isenergized, it operates in a manner previously described to open thedoors.

The relay A also picks up and'closes its make contacts A1. However, theopening of the break contacts 0R7 renders the make contacts A1inefliective to control the 10 speed of the car door motor and the doorsopen at full speed.

When the opening again is cleared, the relays A and B drop out to permita normal door closing operating of the elevator car doors.

In the embodiment of Fig. 3 openingand closing of the doors arecontrolled by a car switch. As previously pointed out, the doors may becontrolled to open automatically as the car stops and to closeautomatically a predetermined time after they open or to close inresponse to registration of car or corridor calls for elevator service.Such automatic operation of doors is well known in the art.

Although the invention has been described with reference to certainspecific embodiments thereof, numerous modifications falling within thespirit and scope of the invention are possible.

I claim as my invention:

1. In a closure system, a structure having an opening, a door, meansmounting the door for movement to close and expose said opening, andobject-detecting means responsive to the presence of an objectsubstantially in the path of said door, said object-detecting meanscomprising a plurality of transmitters each positioned to direct aseparate beam of radiant energy other than visible light substantiallyacross said opening, said beams being spaced from each other in adirection parallel to the plane of the opening, separate detecting meansresponsive to such radiant energy positioned in the path of each of saidbeams for controlling the operation of said door, motive means formoving the door relative to said structure, and translating meanscontrolled by the detecting means for conditioning the motive means toretard movement of the door by the motive means as a function of thenumber of said beams which are interrupted, said translating means beingresponsive to the change in condition of the detecting means followinginterruption of at least a predetermined first number of said beams forretarding movement of the door in a closing direction by the motivemeans, said translating means being responsive to the change incondition of the detecting means only if a second number of said beamslarger than said predetermined first number of said beams areinterrupted for further retarding movement of the door.

2. In a closure system, a structure having an opening through whichobjects may enter and leave the structure, a door, means mounting thedoor for movement to close and expose said opening, motive meanseifective when operated for moving the door to close and expose theopening, and object-detecting means responsive to the presence of anobject in a space substantially in the path of the door during movementof the door in a first direction by the motive means for retardingmovement of the door in said first direction by the motive means, saidobject-detecting means comprising a plurality of separate transmitterseach positioned to' direct a separate beam of infrared energysubstantially across said opening, said beams being spaced from eachother in a direction parallel to the plane of the opening, and separateinfrared detecting means positioned in the path of each of said beams ata position spaced substantially from the associated transmitter alongthe associated beam for controlling the movement of the doorin saidfirst direction said detecting means including means modifying themovement of the door differently for a plurality of diiferent conditionsof interruption of said beams.

3. In a closure system, a structure having an opening, a door, meansmounting the door for movement to close and expose said opening, andobject-detecting means responsiveto the presence of an objectsubstantially in the path of said door, said object-detecting meanscomprising a transmitting device for directing radiant energy into apredetermined area, and a detecting device responsive to said radiantenergy, a first one of said devices being mounted on a portion. of saidstructure other than said door in position to be approached by a leadingedge of said door during closing movement of the door, the second one ofsaid devices being mounted on the leading edge of said door toapproachthe first one of said devices as the door closes, saidtransmitting device directing radiant energy across said opening whenthe door is open towards the detecting device for detection by thedetection device, whereby presence of an object between the devices inthe path of said radiant energy interrupts the detection of radiantenergy by said detecting device.

4. In a closure system, a structure having an opening, first and seconddoors having leading edges adjacent each other when the doors are inposition to close said opening, means mounting the doors forsimultaneous movement towards and from each other relative to thestructure to close and expose the opening, and object-detecting meansresponsive to the presence of an object substantially in the path ofeither of said doors, said objectdetecting means comprising atransmitting device mounted on the first door adjacent the leading edgeof the first door for directing radiant energy across the openingsubstantially towards the leading edge of the second door, and adetecting device mounted on the second door adjacent the leading edge ofthe second door to receive said radiant energy, said detecting devicebeing responsive to said radiant energy for operation from a first to asecond condition, whereby blocking of said radiant energy by an objectpositioned substantially between said doors places the detecting devicein said first condition.

5. In a closure system, a structure having an opening, first and seconddoors having leading edges adjacent each other when the doors are inposition to close said opening, means mounting the doors forsimultaneous move ment towards and from each other relative to thestructure to close and expose the opening, and object-detecting meansresponsive to the presence of an object substantially in the path ofeither of said doors, said object-detecting means comprising atransmitting device mounted on the first door adjacent the leading edgeof the first door for directing radiant energy across the openingsubstantially towards the leading edge of the second door, a detectingdevice mounted on the second door adjacent the leading edge of thesecond door to receive said radiant energy, said detecting device beingresponsive to said radiant energy for operation from a first to a secondcondition, whereby blocking of said radiant energy by an objectpositioned substantially between said doors places the detecting devicein said first condition, and motive means for opening and closing saiddoors, said motive means being operable with said detecting device insaid second condition to effect a predetermined closure of the doors,and said detecting device when operated to said first condition beingeffective for retarding closure of the doors.

6. In a closure system, a structure having an opening, first and seconddoors having leading edges adjacent each other when the doors are inposition to close said opening, means mounting the doors forsimultaneous movement towards and from each other relative to thestructure to close and expose the opening, and object-detecting meansresponsive to the presence of an object substantially in the path ofeither of said doors, said object-detecting means comprising a pluralityof first devices mounted substantially in a row along the leading edgeof the first door, a plurality of second devices mounted substantiallyin a row along the leading edge of the second door, said devices beingarranged in a plurality of pairs each including a separate one of thefirst devices and a separate one of the second devices, the devices ineach of said pairs comprising respectively a transmitting device fortransmitting radiant energy in a beam across the opening between thedoors and a detecting device responsive to the radiant energy receivedfrom the asso:

ciated transmitting device for operation from a first to a secondcondition.

7. In a closure system, a structure having an opening, first and seconddoors having leading edges adjacent each other when the doors are inposition to close said opening, means mounting the doors forsimultaneous movement towards and from each other relative to thestructure to close and expose the opening, and object-detecting meansresponsive to the presence of an object substantially in the path ofeither of said doors, said ohject-detecting means comprising a pluralityof first devices mounted substantially in a row along the leading edgeof the first door, a plurality of second devices mounted substantiallyin a row along the leading edge of the second door, said devices beingarranged in a plurality of pairs each including a separate one of thefirst devices and a separate one of the second devices, the devices ineach of said pairs comprising respectively a transmitting device fortransmitting radiant energy in a beam across the opening between thedoors and a detecting device responsive to the radiant energy receivedfrom the associated transmitting device for operation from a first to asecond condition, the first door including a first door unit and a firstedge unit detachably secured to the leading edge of the door unit, saidfirst devices being mounted on the edge unit for attachment orseparation as a complete assembly relative to the first door unit, andthe second door including a second door unit and a second edge unitdetachably secured to the leading edge of the second door unit, saidsecond devices being mounted on the second edge unit for attachment orseparation as a complete assembly relative to the second door unit.

8. In a closure system, a structure having an opening, first and seconddoors having leading edges adjacent each other when the doors are inposition to close said opening, means mounting the doors forsimultaneous movement towards and from each other relative to thestructure to close and expose the opening, object-detecting meansresponsive to the presence of an object substantially in the path ofeither of said doors, said object-detecting means comprising a pluralityof first devices mounted substantially in a row along the leading edgeof the first door, a plurality of second devices mounted substantiallyin a row along the leading edge of the second door, said devices beingarranged in a plurality of pairs each including a separate one of thefirst devices and a separate one of the second devices, the devices ineach of said pairs comprising respectively a transmitting device fortransmitting radiant energy in a beam across the opening between thedoors and a detecting device responsive to the radiant energy receivedfrom the associated transmitting device for operation from a first to asecond condition, motive means for operating the doors, and commontranslating means responsive to the operation of any of said detectingdevices from the second to the first condition for modifying theoperation of the doors by the motive means.

9. In a control system, a structure having an opening, means forestablishing a plurality of spaced beams of radiant energy in saidopening, first and second translating means having different responsesto the interruption of said beams of radiant energy for exercisingdifferent control functions in said system, said first translating meansbeing responsive to a predetermined change in the condition of at leasta predetermined first number of said beams, and said second translatingmeans being responsive to a pretermined change in the condition of saidbeams only if the number of beams having said predetermined change islarger than the first number.

10. In an elevator system, an elevator car having a door opening throughwhich objects may enter and leave the elevator car, a door, meansmounting the door for reciprocation in a substantially straight path toclose and expose the opening, an energizing circuit, motive meanseffective when energized through said energizing circuit 13 for movingthe door in said path to close and expose the opening, object-detectingmeans responsive to the presence of an object in a space substantiallyin the path of the door during a closing movement of the door by themotive means for retarding closing movement of the door by the motivemeans, said object-detecting means comprising a transmitting device fordirecting across said space a beam of radiant energy, said radiantenergy being focussed into a beam which is parallel to the closingdirection of the door and which is confined substantially to said space,a detecting device in the path of the beam of radiant energy after thebeam has crossed said space, said detecting device being responsive tointerruption of the beam for operation from a first condition to asecond condition, means responsive to operation of the detecting meansto said second condition during a doorclosing operation of the motivemeans for decreasing the closing energy supplied to the motive means bysaid References Cited in the file of this patent UNITED STATES PATENTS1,822,152 Kinnard et a1. Sept. 8, 1931 1,929,273 Crago Oct. 3, 19331,947,079 Ellis Feb. 13, 1934 2,082,941 Burnside June 8, 1937 2,149,177Miller Feb. 28, 1939 OTHER REFERENCES Walker: Photoelectric Cells inIndustry, Pitman Pub.

Corp., New York, 1948, page 189. (Copy in Patent Oifice TechnicalLibrary TK 7872.P5W3.)

